Am I alone in detecting a whiff of smugness in our cool British air? Talking to other business people in Britain, I sense an implicit swelling of pride in our goodish financial performance as old rivals like Germany struggle with high unemployment and a wheezing economy.

Time to be careful, I suggest. Smugness is first cousin of hubris, which is always followed by ruin.

Why am I so gloomy? Because I believe there is a fault line in our national psyche that could have fatal effects on our prosperity. That fault line is a very British belief that the world of ideas is peripheral to our commercial success, whereas I think it is central.

Here's an example - when I saw a Sony Walkman for the first time in the Seventies, Britain's Rank Bush Murphy was a major force in home electronics. Since then Sony has embraced the world of ideas and prospered. Look at us, in contrast.

Kenneth Grange, the great British product designer, told me once that he loved to work in Japan because they saw real commercial value in great design. It is not uncommon for a big Japanese corporation to have a design director on the main board. Now try imagining that here.

A generation after the Walkman, the new must-have music product is the iPod - a brilliantly fresh design idea that has captured everyone's imagination. This breakthrough product has dramatically reversed the fortunes of Apple, which suddenly has something even Microsoft's Bill Gates hasn't got. The iPod is of course the work of a young British designer (Jonathan Ive), but he is working for an American company because it understands that great design can inspire commercial success.

Deep in the darkest corners of the English preoccupation with class is a belief that designing and making things is blue-collar stuff, not white collar. We even show our disdain for manufactured products by calling them all 'widgets' as if to identify them correctly would take us too close to the coal face. Nice middle-class boys become accountants, lawyers or bankers. There's nothing wrong with the professions but a nation needs to do more than advise - it has to create, too.

The irony is that we are world leaders in creating. British advertising agencies are as good as you can find. Ridley Scott, Alan Parker and Anthony Minghella are among the best film directors. The Pompidou centre in Paris was designed by British architect Richard Rogers (with Italy's Renzo Piano) and built by the British firm Ove Arup.

Most ironic of all, the vehicle that revolutionised the way we think about the car was the Mini, a great British design. And who is making a fortune with the new version? Yes, that grand old British company, BMW.

We have the creative talent, we have the design imagination, but we do not have the belief that such talent should be at the heart of a business. I ran a check on which areas the chief executives of the FTSE 100 companies came from and found that 26 per cent had been finance men or women and 29 per cent had been operational managers. How many had been marketing heads? A grand total of 6 per cent.

If we really believe in the power of good ideas to excite the customer, then marketing would be a valued discipline that would lead to the top job. But it didn't in 94 per cent of the top 100 British companies. Before you say most marketing directors just aren't good enough for the top, isn't that the point? In a country where marketing is undervalued, no wonder it doesn't attract the best people. In our strange class culture, marketing is below the salt.

It's a prejudice we breed early. Lots of people want to read media studies at university. It's the study of how mass communication works. Not a bad start for a life in business, you might think. but media studies is widely dismissed by the great and the good as not a 'proper' subject. Victorian novels good, modern films bad is the defining ethos. In the United States, 30 per cent of the workforce is employed in some kind of creative industry, whether it be film, TV, music or journalism and so on. I wonder if they sneer at media studies there?

I started by asking if our smugness at the expense of, among others, the Germans was wise. I touched on the fate of the Mini, now in German hands. BMW also owns Rolls-Royce and Bentley is part of Volkswagen. Meanwhile, Ford of America has snapped up Jaguar and Land-Rover. Their cultures understand the value of a brand.

Meanwhile, our great designers and creative thinkers are facing an ungracious reception at the tradesmen's entrance. Or they are getting out their passports to go to a place where they'll be welcome at the main gates?

· Roger Mavity is chairman of the marketing and public relations firm Citigate Dewe Rogerson.